Raw数据读取

一般相机设备获取的图片数据并不是8位的图片数据，而是16位的Raw数据，也就是说我们看到的图片都是经过对16位的数据进行读取，然后转8位进行显示（中间可能包含各种算法，用于提高图像的画质）。代码中RawDataToImg()函数就是转八位数据的函数，方法有很多，比如线性映射、直方图调光、单平台调光、双平台调光等等。 

bool readRawData(const char* fileName, short* dstData, int nWidth, int nHeight)
{
	unsigned char* srcData = new unsigned char[ nWidth * nHeight * sizeof(short)];
	FILE* fp;
	fp = fopen(fileName, "r");
	if(fp == NULL){
		cout<<"文件打开出错"<<endl;
		return false;
	}
	else{
	    cout<<"文件打开成功"<<fp<<endl;
		fread(srcData, sizeof(unsigned char), nWidth * nHeight * sizeof(short), fp);
		fclose(fp);
	}

	for(int i = 0; i < nWidth*nHeight;i++){
	    dstData[i] = srcData[i*2+1]*256 + srcData[i*2];
	}

	if(srcData){
	    delete []srcData;
		srcData = NULL;
	}
	return true;
}

主函数main( ): 

int main(int argc, char* argv[]){
    string fileName;
	short* srcData;                            //Raw数据类型
	unsigned char* dstData;                    //8位图片类型
	srcData = new short[iWidth * iHeight];     //给数据开辟个空间
	dstData = new unsigned char[iWidth * iHeight];
	//fileName = new char[100];

	if(argc > 1){
	    fileName = string( argv[1] );
	}
	else{
	    cout<<"please input fileName: ";
		cin>>fileName;
		cout<<endl;
	}

	if(srcData == NULL){
	    cout<<"Getting wrong when readding the fileName!"<<endl;
	}else{
		if(readRawData((char*)fileName.c_str(), srcData, iWidth, iHeight)){
		    RawDataToImg(dstData, srcData, iWidth, iHeight);    //将16位Raw数据转8位数据
		}
	}

	Mat img(iHeight, iWidth, CV_8UC1, 1);
	memcpy(img.data, dstData, iHeight * iWidth * sizeof(unsigned char));
	imshow("img", img);
	waitKey(0);

    //释放原先开辟的空间
	if(dstData){
	    delete []dstData;
		dstData = NULL;
	}
	if(srcData){
	    delete []srcData;
		srcData = NULL;
	}

	return 0 ;
}

void RawDataToImg(unsigned char* Dist, short* Src, int iWidth, int iHeight)
{
	short* tmpSrc = Src;
	unsigned char* pDits = Dist;
	long nImageSize = iHeight * iWidth;
	int i =0, j = 0, k=0, sum = 0, nSigma = 0, mMax = 0, mMin = 0;
	int* pHist = new int[HIST_SIZE * sizeof(int)];
	if (pHist != NULL)
	{
		memset((void*)pHist, 0, sizeof(int) * HIST_SIZE);
		for (int i = 0; i < nImageSize; i++)
		{
			pHist[tmpSrc[i] + Y16_AD_MOVE]++;
		}

		nSigma = nImageSize * 0.001;
		for(i = 0 ; i < HIST_SIZE ; i++){
			sum += pHist[i];
			if(sum >= nSigma){
				mMin = i;
				break;
			}
		}
		sum = 0 ;
		for(i = HIST_SIZE - 1 ; i >= 0  ; i--){
			sum += pHist[i];
			if(sum >= nSigma){
				mMax = i;
				break;
			}
		}
		mMin -= Y16_AD_MOVE;
		mMax -= Y16_AD_MOVE;
		float K = (float)((255.0 - 0.0)/(mMax - mMin + 1));//对比度
		float C = (float)((0.0 * mMax - 255.0 * mMin) / (mMax - mMin + 1));//亮度
		for(i = 0 ; i < nImageSize ; i++){
			int nValue = (int)(K * tmpSrc[i] + C -10);
			if(nValue  < 0){
				pDits[i] = 0;
			}else if(nValue > 255){
				pDits[i] = 255;
			}else{
				pDits[i] = (char)nValue;
			}
		}
		delete[] pHist;
		pHist = NULL;
	}
}

matlab代码：

clear all;
close all;

nWidth  = 100;  %图片列数
nHeight = 100;  %图片行数

[filename , pathname] = uigetfile('F:\*', '选择图片');
fid = fopen([pathname  filename]);
s   = fread(fid, 'uint8');
s2  = reshape(s(1:2:end),[nWidth , nHeight]);
s3  = reshape(s(2:2:end),[nWidth , nHeight]);

s4  = (s3)*256+s2;
Image =int16(s4');
fclose(fid);
img = Image;